ABCA1 and ABCG1 are responsible for pumping excesses of this compound into 
ABCA1 and ABCG1 are responsible for pumping excesses of this compound into the bloodstream, and Type C Niemann-Pick disease results in this compound building up in lysosomes. INSIG-1 binding to SCAP is responsible for down-regulating the biosynthesis of this molecule, which is regulated by SREBP-dependent transcription. Esters of this compound are commonly transported by an ApoB100-containing complex, and it can also be transported by chylomicrons. One step in its synthesis is the condensation of acetoacetyl-CoA with acetyl-CoA, which is catalyzed by HMG-CoA synthase, and the step catalyzed by HMG-CoA reductase is inhibited by statins. It contains 4 fused rings, is the precursor for all steroid hormones and bile salts, and regulates membrane fluidity. HDL and LDL are the "good" and "bad" kinds of, for 10 points, this common 27-carbon lipid.
ABCA1 and ABCG1 are responsible for pumping excesses of this compound into the bloodstream, and Type C Niemann-Pick disease results in this compound building up in lysosomes.
{Cholesterol}